[GIT PULL] cgroup fixes for v3.7-rc5
From: Tejun Heo <hidden>
Date: 2012-11-13 16:26:34
Also in:
lkml
Subsystem:
security subsystem, the rest · Maintainers:
Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
Please pull from the following branch to receive fixes for v3.7-rc5.
It contains two fix patches for device_cgroup. One fixes a regression
introduced earlier in 3.7 cycle where device_cgroup could try to
dereference the NULL parent of the root cgroup. The other one is RCU
usage fix.
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-3.7-fixes
Thanks.
---
Aristeu Rozanski (1):
device_cgroup: fix unchecked cgroup parent usage
Tejun Heo (1):
device_cgroup: fix RCU usage
security/device_cgroup.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 842c254..b08d20c 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c@@ -164,8 +164,8 @@ static void dev_exception_clean(struct dev_cgroup *dev_cgroup) struct dev_exception_item *ex, *tmp; list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) { - list_del(&ex->list); - kfree(ex); + list_del_rcu(&ex->list); + kfree_rcu(ex, rcu); } }
@@ -298,7 +298,7 @@ static int may_access(struct dev_cgroup *dev_cgroup, struct dev_exception_item *ex; bool match = false; - list_for_each_entry(ex, &dev_cgroup->exceptions, list) { + list_for_each_entry_rcu(ex, &dev_cgroup->exceptions, list) { if ((refex->type & DEV_BLOCK) && !(ex->type & DEV_BLOCK)) continue; if ((refex->type & DEV_CHAR) && !(ex->type & DEV_CHAR))
@@ -352,6 +352,8 @@ static int parent_has_perm(struct dev_cgroup *childcg, */ static inline int may_allow_all(struct dev_cgroup *parent) { + if (!parent) + return 1; return parent->behavior == DEVCG_DEFAULT_ALLOW; }
@@ -376,11 +378,14 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, int count, rc; struct dev_exception_item ex; struct cgroup *p = devcgroup->css.cgroup; - struct dev_cgroup *parent = cgroup_to_devcgroup(p->parent); + struct dev_cgroup *parent = NULL; if (!capable(CAP_SYS_ADMIN)) return -EPERM; + if (p->parent) + parent = cgroup_to_devcgroup(p->parent); + memset(&ex, 0, sizeof(ex)); b = buffer;
@@ -391,11 +396,14 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, if (!may_allow_all(parent)) return -EPERM; dev_exception_clean(devcgroup); + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; + if (!parent) + break; + rc = dev_exceptions_copy(&devcgroup->exceptions, &parent->exceptions); if (rc) return rc; - devcgroup->behavior = DEVCG_DEFAULT_ALLOW; break; case DEVCG_DENY: dev_exception_clean(devcgroup);